• 농촌계획
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• 제21권3호
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• pp.1-17
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• 2015

The value of rice-fields is being graded down in Korea because it has been estimated only from the size. The purpose of this study is to suggest a management plan in which the location and the size of valuable rice-fields for conservation are based on the results of appraising the worth of ecosystem services of rice-fields in Chungcheongnam-do region. The study is as follows; (1)selecting the indicators for evaluating the ecosystem services of rice-fields considering both general functions and special functions in the regional environment conditions, (2)classifying the grades of rice-fields in ecosystem service values, (3)suggesting the location and the size of valuable rice-fields for conservation, (4)calculating the total economic value of the ecosystem services of rice-fields. The results of this study are that the valuable rice-fields' locations for conservation are the grade I rice-fields and their total area is 100,000ha. Also, the value of the ecosystem services of rice-fields in Chungcheongnam-do region was equivalent to 32.8 trillion won. This amount is over 18 trillion won more than the amount obtained if the total rice-fields in Chungcheongnam-do region were to be transformed to other land-use types. The value of ecosystem services should be considered in the future when appraising the worth of rice-fields, and methods of estimating the ecosystem services of rice-fields need to be developed with a more objective and suitable index.

• 전자공학회논문지A
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• 제32A권10호
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• pp.43-50
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• 1995

A laser diode(LD) structure consisting of a single 150$\AA$ $Al_{0.07}$Ga$_{0.93}$As quantum well active region operating at ${\lambda}$=809nm, cladded with an AlGaAs graded-index separate confinement heterostructure, has bes been grown by MOCVD. Temperature coefficient of wavelength is approximately 0.2nm $^{\circ}C$ for the diode. The active aperture consists of five emitters separated from each other by means of SiO$_{2}$ deposition and stripe formation, which creates insulating regions that channel the current to 100-$\mu$m-wide stripes placed on 450-$\mu$m centers. From a typical uncoated LD, the output power of 0.8W has been obtained at a 1$\mu$s, 1kHz pulsed current level of 2.0$\AA$, which results in about 64% external quantum efficiency. The threshold current density is 736A/cm$^{2}$ for the case of 500$\mu$m cavity length LD's. The measure of an internal quantum efficiency was 75.8% and the internal loss 4.83$cm^{-1}$ . Finally, 3.1W output power has been obtained at a 1$\mu$s, 1kHz pulsed current level of 9A from the 500$\mu$m-aperture LD array with 460-$\mu$m- cavity length.

• 한국물환경학회지
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• 제25권3호
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• pp.404-410
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• 2009

In this study, research for physical and chemical characteristics were conducted through analysis of sediments, grading and heavy metals (e.g., Mn, Cu, Cd, Zn and Pb ) in sewers which are classified by drainage types. After that, cement solidification and yellow soil calcinations made heavy metals stabilized and then, ways of recycling it were examined. The grain size distribution of all sediments was relative graded. When evaluating heavy metal pollution through index of geoaccumulation (Igeo), Cu showed moderately pollution or strong pollution in forest and street site and Zn was assessed by moderately pollution in military, residential, and street site. Analysis of Pearson Correlation coefficient of heavy metal indicated that all items in street site have tight relationship respectively. Especially, Cd-Zn, Cu-Pb, Cu-Mn, and Pb-Mn have relationship at 99% confidence intervals in statistical analysis. Recycling it with cement solidification was satisfied with compressive strength standard under 55% deposit contents and Zn, Pb, Mn were stabilized effectively. If time and temperature plasticity and compressive strength would be standard, it is revealed that yellow soil calcinations is valuable aggregate when it has 50-60 Wt% contents. When considering economic feasibility and stabilization of heavy metals, cement solidification would be more appropriate than yellow soil calcinations as solution to recycling.

• Journal of Korean Neurosurgical Society
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• 제51권1호
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• pp.8-13
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• 2012

Objective : This is prospective study of clinical outcomes of percutaneous plasma disc coagulation Therapy (PDCT) in patients with herniated lumbar disc disease (HLD) to evaluate the safety and efficacy in its clinical application and usefulness as a reliable alternative to microscopic discectomy. Methods : Forty-six patients were enrolled in this study from April 2006 to June 2010. All patients had one-level HLD. Disc degeneration was graded on routine T2-weighted magnetic resonance Image (MRI) using the Pfirrmann's grading system and all index levels were grade 3 and grade 4. Indications for surgery were radiculopathy caused by disc protrusion with soft consistency. MRI was done at one month after the procedure in all patients to check post-PDCT change. The clinical outcomes were evaluated using Visual Analog Scales (VAS) score and MacNab's criteria. Results : This study was approved by the Institutional Review Board of our institution. The age of the study population ranged from 16 to 59 years with a mean age of 37.2 years. There were 29 males and 17 females in this study. The mean period of clinical follow-up was 21 months. The average preoperative VAS score for radiculopathy was $7.4{\pm}1.4$, while the final follow-up VAS score was $1.4{\pm}0.7$ (p<0.001). In MacNab's criteria, 41 patients (89.1%) had achieved favorable improvement (excellent and good) until later follow-up. There were one patient from infection and two patients who needed to convert to open discectomy. Conclusion : PDCT is a safe and efficient treatment modality in a selective patient with HLD.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.126-126
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• 2011

수직으로 정렬된 1차원 ZnO nanorod arrays (NRAs)는 효율적인 반사방지 특성의 기하학적 구조를 갖고 있어, 크기와 모양 그리고 정렬형태의 다양한 설계를 통해 빛의 흡수율과 광 추출효율을 증가시켜 광전소자 및 태양광 소자의 성능을 향상시킬 수 있으며, 최근 이러한 연구에 대한 관심이 집중되고 있다. 본 연구에서는 ZnO NRAs의 넓은 표면적과 불연속적인 독특한 표면을 활용하여 광학적 특성을 효과적으로 개선하였다. 실험을 위해, thermal evaporator를 사용하여 Au와 Ag 그리고 e-beam evaporator를 사용하여 $SiO_2$를 ZnO NRAs 표면에 여러 가지 조건으로 증착하여, 독특한 계층 나노구조의 형성과 광학적 특성을 관찰하였다. 표면 roughness가 큰 FTO/glass 위에 수열합성법을 통해 끝이 뾰족하고, 비스듬히 정렬된 ZnO nano-tip array에 Au를 증착할 경우 ZnO/Au core/shell 구조가 형성되며, Au의 광 흡수율이 매우 크게 증가함을 관찰할 수 있었다. 반면 flat한 표면위에 빽빽하게 수직으로 정렬된 ZnO NRAs를 성장시켜 그 위에 Ag를 증착할 경우, evaporated Ag flux가 ZnO nanorod의 사이에 scattered 되어 ZnO nanorod 기둥의 측면에 직경이 50 nm 이하인 nanoparticles이 decorated 되어 국소표면플라즈몬 현상이 관찰되었으며, 이러한 효과를 통해 입사되는 빛의 흡수율을 효과적으로 증가시킬 수 있었다. 또한, ZnO NRAs의 표면에 $SiO_2$를 e-beam evaporator를 이용하여 증착할 경우, 자연적으로 vapor flux와 ZnO nanorod 사이에 oblique angle이 $80^{\circ}$ 이상으로 증가하여 $SiO_2$ nanorods가 자발적으로 형성되어 ZnO/$SiO_2$ branch 계층형태의 나노구조를 제작할 수 있었다. 이러한 구조는 유효 graded refractive index profile로 인해 기존의 ZnO NRAs보다 개선된 반사방지 특성을 나타냈다. 이러한 계층 나노구조의 광학적 특성을 시뮬레이션을 통해 이론적으로 분석을 통해 광전자 소자의 성능의 개선에 대한 적용 가능성을 조사하였다.

• The Korean Journal of Pain
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• 제12권1호
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• pp.81-86
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• 1999

Background: Essential hyperhidrosis is a condition with excessive sweating, which may be localized in any parts of the body. Thoracic sympathectomy has been a surgical procedure for the management of hyperhidrosis. Methods: We studied 30 ASA I and II patients suffering from severe hyperhidrosis. Bilateral upper thoracoscopic sympathectomy of $T_{2-4}$ was performed in 30 patients under general anesthesia. Anesthesia was induced with 2.5% thiopental sodium 5 mg/kg and succinylcholine chloride 1 mg/kg and was maintained with enflurane 1~2 Vol% and $N_2O-O_2$ mixture adjusted to maintain $SpO_2$ greater than 96%. During anesthesia, invasive arterial pressure, heart rate, EKG, $SpO_2$ and capnography were monitored. Skin temperature was measured with thermister probes attached to the index finger of each hand. An increase in temperature after cautery confirmed success of the sympathectomy. Results: There were 14 men and 16 women whose ages ranged from 16 to 46 years old (mean age 22.2). Of these patients, 13 patients had complained of palm-sole hyperhidrosis, 9 of palm-sole-axilla hyperhidrosis, 4 of palm-sole-face hyperhidrosis and 4 of palm-sole-axilla-face hyperhidrosis. The provocative factors of excessive sweating were tension and stress from interpersonal relationships. There was positive familial history in 37%. The most common complication was compensatory hyperhidrosis in 23 patients comprising 76%. Other complication included peumothorax (4 patients), hemothorax (1 patient), ipsilateral Horner's syndrome (1 patient) and paresthesia of right arm (1 patient). The degree of satisfaction was graded as good, fair and poor with 15, 12 and 3 patients, respectively. Conclusions: Thoracoscopic sympathectomy with VATS is an efficient, safe and minimally invasive surgical procedure for essential hyperhidrosis.

• 동아시아식생활학회지
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• 제27권1호
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• pp.78-87
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• 2017

The objective of this study was to investigate the effects of various washing waters on the quality and safety characteristics of eggs during storage. Eggs were washed with tap water, 100 ppm of sodium hypochlorite, or 30 ppm of slightly acidic electrolyzed water and stored at $10^{\circ}C$ and $20^{\circ}C$. Effects of various washing waters on reduction of Salmonella Enteritidis and aerobic plate counts and survival of S. Enteritidis on egg shells were also analyzed at $10^{\circ}C$ and $20^{\circ}C$ for 25 days. As an index of quality, haugh unit, weight reduction, and pHs of egg white and egg yolk were measured. Reduction percentages of haugh unit and weight were higher at $20^{\circ}C$ than at $10^{\circ}C$. Egg qualities were less affected by tap water, slightly acidic electrolyzed water, and sodium hypochlorite, regardless of storage temperature. The greatest reductions in aerobic plate counts and S. Enteritidis were observed with slightly acidic electrolyzed water. The level of S. Enteritidis on egg shells gradually decreased during 20 days of storage at both $10^{\circ}C$ and $20^{\circ}C$, whereas S. Enteritidis survived longer at $20^{\circ}C$ than at $10^{\circ}C$. S. Enteritidis was not detected in eggs at $10^{\circ}C$, 2.13 log CFU/g of S. Enteritidis was detected in eggs washed with sodium hypochlorite after 20 days of storage at $20^{\circ}C$, indicating that S. Enteritidis penetrated into the egg shell during storage at $20^{\circ}C$. In conclusion, slightly acidic electrolyzed water increased microbial reduction and least affected quality of washed eggs. Thus, slightly acidic electrolyzed water can be recommended for washing of graded eggs, at retail markets.

• 대한수의학회지
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• 제44권4호
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• pp.607-613
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• 2004

Helicobacter pylori (H. pylori)-infection is an important pathogen of stomach cancer after chronic gastritis and ulceration in the stomach and duodenum. However, the virulences of H. pylori strains have not been well-defined between clinical isolates. This study was designed to establish water-immersion-restraint stress (WIRS) model in mongolian gerbil for comparison of pathogenicity of H. pylori strains. To determine an optimal duration time for WIRS model in gerbil, 5-week-old Mongolian gerbils were divided into different groups by WIRS duration time. After graded duration of WIRS, the macroscopic ulcer index (UI) was measured with the stomach and duodenum of sacrificed animal. There were no significant differences between male and female in same duration group. However, the UI increased significantly in a time-dependent fashion. The group of 6 hours-WIRS animals showed severe hemorrhage and ulceration in their stomach and duodenum. On the other hand, the very mild lesions induced in 2 hours-treated animals. Therefore, we determined an optimal duration time for WIRS model in gerbil as 4 hours. Thereafter, we evaluated whether this WIRS model in gerbil could be used as an useful tool for in vivo comparison of pathogenicity of H. pylori strains by enhancement of pathological severity in H. pylori-infected gerbils. Mongolian gerbils were divided into H. pyloriinfected and PBS-inoculated groups. Thereafter, they were divided again into 4 hours-WIRS and no WIRS subgroups. After treatment, the severity of pathological changes was evaluated in a same manner with previous duration-determining experiment. When the animals were exposed to WIRS, the UI was significantly higher in the infected group than in the uninfected group. These results suggested that the established gerbil-WIRS model in this study enhanced effectively the severity of pathogenic changes in the H. pylori-infected Mongolian gerbils and could be used as an useful tool for in vivo comparison of pathogenicity of H. pylori strains.

• Advances in nano research
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• 제7권4호
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• pp.249-263
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• 2019

In the current paper, an exact solution method is carried out for analyzing the thermo-mechanical vibration of curved FG nano-beams subjected to uniform thermal environmental conditions, by considering porosity distribution via nonlocal strain gradient beam theory for the first time. Nonlocal strain gradient elasticity theory is adopted to consider the size effects in which the stress for not only the nonlocal stress field but also the strain gradients stress field is considered. It is perceived that during manufacturing of functionally graded materials (FGMs) porosities and micro-voids can be occurred inside the material. Material properties of curved porous FG nanobeam are assumed to be temperature-dependent and are supposed to vary through the thickness direction of beam which modeled via modified power-law rule. Since variation of pores along the thickness direction influences the mechanical and physical properties, porosity play a key role in the mechanical response of curved FG nano-structures. The governing equations and related boundary condition of curved porous FG nanobeam under temperature field are derived via the energy method based on Timoshenko beam theory. An analytical Navier solution procedure is utilized to achieve the natural frequencies of porous FG curved nanobeam supposed to thermal loading. The results for simpler states are confirmed with known data in the literature. The effects of various parameters such as nonlocality parameter, porosity volume fractions, thermal effect, gradient index, opening angle and aspect ratio on the natural frequency of curved FG porous nanobeam are successfully discussed. It is concluded that these parameters play key roles on the dynamic behavior of porous FG curved nanobeam. Presented numerical results can serve as benchmarks for future analyses of curve FG nanobeam with porosity phases.

• Journal of Periodontal and Implant Science
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• 제52권1호
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• pp.54-64
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• 2022

Purpose: This in vitro study was conducted to evaluate the effects of different debridement techniques and conditioning procedures on root surface morphology and blood clot stabilization. Methods: Two debridement techniques (curette [CU] vs. high-speed ultrasound [US]) and 2 conditioning procedures (ethylenediaminetetraacetic acid [EDTA] and phosphoric acid [PA]) were used for the study. Seven experimental groups were tested on root surfaces: 1) no treatment (C); 2) CU; 3) US; 4) CU+EDTA; 5) US+EDTA; 6) CU+PA; and 7) US+PA. Three specimens per group were observed under scanning electron microscopy (SEM) for surface characterization. Additional root slices received a blood drop, and clot formation was graded according to the blood element adhesion index by a single operator. Data were statistically analyzed, using a threshold of P<0.05 for statistical significance. Results: The C group displayed the most irregular surface among the tested groups with the complete absence of blood traces. The highest frequency of blood component adhesion was shown in the CU+EDTA group (P<0.05), while no differences were detected between the CU, US+EDTA, and CU+PA groups (P<0.05), which performed better than the US and US+PA groups (P<0.05). Conclusions: In this SEM analysis, EDTA and conventional manual scaling were the most efficient procedures for enhancing smear layer removal, collagen fiber exposure, and clot stabilization on the root surface. This technique is imperative in periodontal healing and regenerative procedures.